Sunday, December 14, 2008

Into the Notch


So you may be asking what's the notch?The notch,simply explained,is the area on the stern of the barge where the bow of the tug fits into.Everybody got that?No,me either.That's why I took a video to better explain myself.However let me try again,in detail,with words.So the bow of the tug is "pointed".Most offshore barges have an area on the stern of them where an offshore tug can fit into,referred to as the notch.Now the reasoning behind this set up is quite simple.The tug fits snugly into the notch for a few different reasons.First and most importantly is better control.The tighter in the notch the tug can get the better the control.So what happens after the tug gets in the notch?How do they stay there?Easy answer,either cables,or lines or a combination of the two,are stretched out from the stern of the tug up onto the barge.The next step is tightening them using the large tow drum located on the stern of the tug.These drums,also referred to as the suitcase drum or money maker,are extremely powerful and often run by hydraulics.Oddly enough this set up is becoming out dated as new tugs emerge with a new set up.As hydraulics become more efficient,these new tugs are equipped with a pin system.Referred to as ATB or ,articulated tug and barge units,these new tugs have become the wave of the future.They simply come into the notch and a set of hydraulic pins,very large ones,emerge from the bow of the tug and lock into "holes" in the barge notch.This system allows them to be primarily a "push" boat as they can routinely take 10 foot seas with no worry of the pin system faulting.The old cable and line system will not tolerate more than 3 foot waves.So as the old system barges head offshore they have to set free and continue offshore by towing.Then upon arrival at the next port of call they break down again to get into "pushing gear" to dock the barge.As you might imagine this system causes much more work for the deck crew,but hey at least I have a job.If you have questions,ask away!


{nUtTyPrOfFeSsOr} said...

That makes since- do most boats have similar notch angles and depths in size classes?
All up in dat notch.

tugboatdude said...

Most offshore boats do have around the same angle.The rubber,tires,panel rubber etc.,get squeezed into the norch.The pushing wires are tightened up and bingo bango you are done.That's why the ATB is such a great idea.It's the tightest fit in the notch so it has perfect ability to move and simply can't break free with the hydraulic pin system.The cables on the old style tugs have a breaking point and from experience it isn't pretty when they go.good question my brother.

tugboatdude said...

Also as I didn't mention before,another plus of the ATB is the amount of cargo they can push.The barges are typically 200,00 barrel barges and bigger.They can move almost as much as a small ship.One more plus,as if you need one,is the crew is much smaller than that of a ship.USCG requires "adequate crewing" on all offshore vessels,depending on length.That's the loophole if you will.Since the tug isn't technically part of the barge they only have to crew for the length of the tug.This keeps the crew to around 6-8 where as a ship the same length as the tug and barge together would have a crew around money,money.